HOW TO SHOOT 400 meter starts.
***introduction
Still not shoot do not usually represent how much it, 400 m. offer the, who really wants to learn, to measure the distance and estimate the range. You will be surprised, as it is really far away and seemingly impossible aimed fire at this distance. This is a very important point, you should represent what will be faced.
Having read the post carefully, you will understand, that this distance is available to almost everyone, who hold a rifle standing.
***Why 400 m?
On the flight bullets are different forces, which cause it to move along a ballistic trajectory. Calculate the trajectory is not an easy task enough. At the beginning of flight, these forces are not greatly deflect the bullet. Therefore, they can simply be ignored to a certain distance.
Let's look at what kind of forces and with what the distance should be taken into account.
For example, take 308 caliber.
Scenar Silver jacket , the weight 9,10 bal.koef. 0,4 speed 800 m / s
– The attraction of the earth at a distance 150 m.
– crosswind 5 m / s at a distance 180 m.
– Height, if on 1 km. climbed the hill,at a distance 500 m.
– temperature change 20 degrees 600 m.
– derivation 650 m.
– The rotation of the earth on 900 m.
– other forces will affect the long range.
It turns out, if you want to get on 200 meters in the growth and even the head shape, You can do nothing uchityvat.Na 400 We count only meters away and the wind. Nothing else is required.
Group “SWAT tactics”
Therefore, we choose to distance 400 m. At greater distances have to seriously study ballistics, that is not included in the post format.
Next, we analyze in detail each item individually, that there was a clear picture of what is happening.
***Departure angle or internal ballistics
There are things that are more important than distance measurements of winds and temperatures. This section is called “internal Ballistics”. Besides, what “internal Ballistics” It does not shoot accurately with automatic and semi-automatic weapons, it still gives some adjustments and precision weapons. All these internal resonance vibrations can be reduced to a single parameter, which is called “exit angle”. On the second, Bullet flies are not exactly on the axis of the barrel, which was before the shot, it is necessary to deviate. In any firearm. It suffers all firearms. To reduce this angle boltovikah even stopped doing the fly. AND, usually, the barrel does not touch the bed. This angle depends on, how do you keep weapons, both pressed the butt, How does the position of the arrow. Different people have the same rifle with the same gun will get to different places. Therefore, the first rule: Targeting only the most. No one can adjust your rifle.
departure angle will change the position of the arrow. Lying to stop, with bipod, sitting , standing. Each angle position is different arrow. I have a bunch of different calibers. the actual shooting and measurements have shown that the amount of change in the emission angle depends on the strength of return. The greater efficiency, the stronger dependence. Almost imperceptible abnormalities were melkashki and a strong dependence on the smoothbore 12 caliber, bullet. In semiautomatic dependence is stronger than that of the bolt, even on the same caliber. How to fight it? Came to mind just to have for each position your table amendments. Personally, for myself I made a table standing and shooting with a bipod. As it turned out, in practice, it does not prevent to have a table and lying to stop. The fore-end is at hand, is to stop the monotony of stiffness.
Emission angle depends on the chuck mark. Charge each cartridge and he flew from a different angle. His departure does not fit into the external ballistics. Contrary to all the calculations on any ballistic calculators. That is no calculator can not calculate your trajectory, since it can not calculate the internal ballistics and the emission angle. Maybe this is due to a general distrust of the calculators shooters with experience.
Departure angle varies vertically. Almost does not change the horizontal. Which greatly simplifies the task of. The idea of zeroing is as follows. windage drum We adjusted to zero and will not touch. But the vertical correction will twist depending on the situation. Each hand position and type of cartridges must comply with the figure on the vertical drum. Changed the cartridge and pereschelknuli amendment. Changed posture from a standing position on a bipod, pereschelknuli drum in the desired position and all. You need to have some sign holder and in what position what should be the number on the drum. Basically, if sometimes shoot, this tablet is easy to remember. Naturally, it will be the individual, even if one rifle will shoot different people, then each will have its own label.
***straight shot
straight shot- a shot from a firearm, wherein the projectile trajectory (bullet) It does not rise above a predetermined target height. Within the range of P. at. Shooting is conducted on a permanent installation of the sight, corresponding to this range, which simplifies and accelerates the tip of arms, especially when shooting at moving targets. Dictionary of Military Terms. - M.: Military Publishing Comp. A. M. Plekhov, FROM. D. Shapka. 1988
With this deal is not difficult. The barrel is located below sight. Therefore the bullet after departure is below the line of sight. Since the stem axis at an angle to the axis of sight, bullet starts to rise.
At some distance it intersects the axis of the barrel. This place is called the first zero. Next flight above the axis of the barrel. Under the force of gravity of the bullet begins to fall and once again crosses the axis of the barrel. This distance is called the second zero. If the maximum elevation between zeros suits us, we can assume that it is a straight shot.
***Temperature effect on the flight of the bullet
Temperature changes of sound velocity and density of air. Bullet resistance of air is approximately quadratic dependence on the speed, and the rate in ballistics considered in mahah. That is, in the sound speeds. Changing the speed of sound necessarily affect the resistance to bullets. The second factor, is the air density. Cold air is denser than hot, which also affects the resistance.
Now consider how much influence on the flight of bullets temperature.
Scenar Silver jacket bal.koef. 0,400 Beg. speed 800 m / s
if you change the temperature on 1 degrees, this will shift the trajectory 6 mm at a distance 600 m.
amending 10 degrees
distance 200 m – 2 mm.
distance 400 m – 15 mm.
distance 500 m – 28 mm.
distance 600 m – 58 mm.
For our purposes, 28 millimeters at a distance 500 meters mean nothing.
If we compare the temperature +20 and -20 Celsius. ie drop in 40 degrees.
distance 200 m – 5 mm.
distance 400 m – 63 mm.
distance 500 m – 124 mm.
distance 600 m – 287 mm.
already sensitive. There is another fact. In winter you wearing thick warm jacket. it will change the overall ballistics and emission angle. This effect is even greater, than change the trajectory of the temperature. It is therefore desirable to have two plates: Winter and summer. zeroing should be conducted in the clothes in which then plan to hunt. Thus, we take into account and a jacket, and the temperature dependence of the trajectory. for special perverts can do a sign and spring – autumn)))
***Air pressure.
air pressure changes its density. The denser the air the greater will be hampered by a bullet.
Let's see how to change the trajectory and at a pressure 740 mmHg. against 780 mmHg.
at a distance 200 m 4 mm.
at a distance 400 m 37 mm.
at a distance 500 m 87 mm.
at a distance 600 m 163 mm.
if the sighting to do with the average value 760 mm, even strong pressure change declines less 5 see 500 m. In my opinion the air pressure can be disregarded.
Now consider the mountain conditions. We will compare the difference between sea level and altitude.
height 200 m
distance 200 m. 0 mm.
distance 400 m. 15 mm.
distance 500 m. 30 mm.
distance 600 m. 55 mm.
height 1000 m
distance 200 m. 5 mm.
distance 400 m. 59 mm.
distance 500 m. 130 mm.
distance 600 m. 251 mm.
height 2000 m
distance 200 m. 8 mm.
distance 400 m. 105 mm.
distance 500 m. 232 mm.
distance 600 m. 553 mm.
If you live on the plain, the air pressure can be ignored,but if you have subminutny bolt and going to fire high in the mountains, it can be a separate plate or plates for the shooting at a height.
***derivation.
Derivation appears on rifles. The bullet is rotated at a tremendous speed of the order 160 thousand. rpm. Gyroscopic effect keeps the bullet from tumbling. In flight, the force of gravity and the incoming wind changes bullets axis of rotation, according to the trajectory. When changing the rotational axis deflects bullet gyroscopic effect left or right, It depends on the direction of cutting. If we Strelna in absolutely calm weather, the bullet at the right cutting begins to deviate in the right.
Let's look at how many. Scenar Silver jacket , the weight 9,10 bal.koef. 0,400 Beg. speed 800 cutting step 0,32 m(twist 12.6)
distance 200 m 6 mm.
distance 400 m 30 mm.
distance 500 m 52 mm.
distance 600 m 87 mm.
as we see – there is a deviation, but quite bearable.
bullet rejects not only gravity, but also wind. Derivation of crosswinds will deflect the bullet up or down. It depends on the wind direction and the direction of rotation.
let's see what will be the value of the variation in a crosswind 5 m / s.
distance 200 m 19 mm.
distance 400 m 39 mm.
distance 500 m 49 mm.
distance 600 m 59 mm.
At a distance of up to 500 meters derivation does not affect much. Therefore, you can just forget about it.
***ballistic coefficient
AT 1881 year, in Germany, croup (Krupp) first and streamlined collected data on the influence of air resistance to the bullet flight. If you know, how fast the bullet loses speed, it is possible to construct a trajectory.
AT 19 century caliber bullets used 10,67 mm. In subsequent centuries the caliber began to decrease. The formula based on the bullet Krupp no longer fit. If the bullet has a tighter form, but smaller – the resistance will be proportional. It turned point enough factor and all coincided. It appeared ballistic coefficient.
Further development of small arms has led to the creation of new bullets to form an arc. They do not fit the schedule of the bullet Krupp braking
So they decided to create other charts(dragfunktsii). Some are included in the program.
G1 – A model for the bullet Krupp.
G7 – for bullets with a long tapered tail (angle 7. 30′) and tangential ogive radius 10 calibres
GS – Model for the circular bullets
RA4 – For .22LR caliber
If known ballistic coefficient, it will be and the path. Unfortunately, its manufacturer does not always indicate his. Worse still indicate not correct. But almost always manufacturer indicates distance speed. This is sufficient to determine the BC.
***Prystrelka
Ranging starts with “boresight”. Take a laser cartridge, inserted into the barrel and turn the sight, until the point of the cartridge align with crosshair.
If you do not have a laser cartridge, it is possible and without it. To do this, you need to fix the rifle motionless. better to do this with the sighting of the machine. the machine a lot of options. You can use any.
Aim the rifle at a target. We look through the barrel in the center of the target. then twist the sheep. We set the crosshair in the center of the target.
It will be assumed that the boresight made.
Then begins the real zeroing. With the machine can not shoot. If you adjust the loom, It will be sighted machine departure angle. The rifle will shoot accurately only, when the machine is on. If you will continue to use the rifle separately from the machine, the shoot will have with the position from which you will be hunting.
Shoot several times, to determine the accuracy of the center. At the same time we see the accuracy of the rifle. Then fasten the rifle in the machine. We set up the machine so, to aim the crosshair looked exactly the center of the target.
then gently, not to move the rifle, spinning the reels, set in the center of the crosshair accuracy. We relax the screws on drums and displace the scale to zero. tighten bolty.Vse rifle zeroed.
Admittedly this is a special case of the position and the cartridge that you shot.
***Wind.
This is the most difficult moment in the shooting at a decent distance. Wind is very difficult to calculate. to be precise, its hard to measure. If we could measure the wind on the race, the calculation is done easily. Even if you have an anemometer, you can measure the wind just at the point where you are. And what about the wind and the target in the middle distance, We can only guess. Wind blows at a constant speed, often with gusts, changing every second. You can rely on the experience and luck.
A little bit about the wind demolition bullets. There is misconception that the wind pressure on the wall of the bullet and therefore it changes the trajectory. In fact, the situation is a little different. The wind, as it were slightly changes the angle of the incoming flow and the bullet is guided towards this stream. The strength of the change of the trajectory depends on the speed of the bullet. More on anything. Do you want to bullet less wind drift, purchase fast gauges. for example 300 caliber.
example: Scenar Silver jacket , the weight 9,10 bal.koef. 0,400 crosswind 5 m / s
calculation for the open sight. so instead of a drum of numbers fall in centimeters. Deviation crosswind 5 m / s.
on 100 meters deviation 2 cm.
on 200 meters deviation 10 cm.
on 400 meters deviation 43 cm (ne got in listing)
I have been thinking how to decorate a deviation from the wind. I decided to do both in the army guidance for SVD.
5 m / s is the average wind.
10 m / s is a strong wind resulting value should be multiplied by two
like this. wind 10 m / s
on 100 meters deviation 4 cm.
on 200 meters deviation 20 cm.
on 400 meters deviation 86 cm
2.5 m / s is a gentle breeze, then divide by two
on 100 meters deviation 1 cm.
on 200 meters deviation 5 cm.
on 400 meters deviation 22 cm
Aiming point mentally move against the wind. at a specified distance. If the wind is purely a side, the place of sight in the side. If the wind counter, the point moves over a target, that is, it did not move us. On all intermediate angles of approximately pretends where she will. There will only experience.
Yes, even the speakers last. It was a place on the business card, He added to anticipation. it will be held as a target while flying bullet, if the vehicle speed 5 kmh.
***sight drums.
There are scopes with drums, which closes the lid. These scopes are designed for hunting and are not designed for long-distance. With these scopes you shoot at a distance of only a direct shot. Depending on the situation, you set the desired value on the drum and have a straight shot to 200 m. That's enough for all kinds of hunting.
Tactical drums to rapidly change the value, depending on the distance. Them we will shoot up 400 m.
For accurate shooting, we need to know the distance. this usually use laser rangefinders, or in any way possible.
***conclusion
for distance 400 meters other forces are so small that they will not consider.
For shooting at 200 meters do not need anything. In addition to the initial zeroing under the favorite posture shooting.
at a distance of up to 400 meters need to have a crib in the notebook(wood), how to spin the drum at a distance and be able to take into account the wind.
Shooting at a distance 400 meters available to any adequate arrow.
